A 17-room spread owned by a super-rich hedge-fund king is the city’s grooviest pad, adorned with a pop-art “diamond” the size of a water buffalo.

The penthouse terrace at 1 Sutton Place South has been turning heads since owner Richard Perry and his fashion-designer wife, Lisa, installed the massive green stainless-steel sculpture by famed modern artist Jeff Koons.

According to Artnet.com, the 5-foot-high work was sold in 2005 for $2.3 million and was part of a series of similar sculptures of gigantic diamonds. A blue version sold for $11 million.

The green sculpture, which was hauled to its spot with a crane, isn’t the only bling on the terrace. A wall behind the artwork is encrusted with smaller, flower-shaped gemstones.

The sculpture has run into some trouble since it was installed in 2007.

Neighbors who live across the street in a penthouse at 14 Sutton Place complained that the light reflecting off it was burning like lasers through their windows, and workmen had to adjust the diamond’s positioning, a source said.

It has also not been a hit with amateur art critics.

“I think it’s as ugly as it comes,” said Juergen Thieme, who lives across the street at 2 Sutton Place. “But everyone has a right to his kind of beauty. It’s not my kind. People to whom I’ve spoken don’t care too much for it, either.”

According to Fortune magazine, the Perrys like to show off their art pieces to visitors at their penthouse, which they bought in 2000 for $10.9 million.

“When you go to their house, they give you an art catalog and literally take you on a tour,” a source told the mag.